What do all isomers of octane have?

A formula of ${C}_{8} {H}_{18}$........
I don't know how many isomers octane has.......10? 20? You would probably find the number on the web, and of course some of these isomers will allow geometric isomerism. The stuff that we pump into our motors is $\text{2,2,4-trimethylpentane}$